In recent years, mobile devices have witnessed a massive deployment. A large number of mobile devices include sensors that support determining geo locations and orientations of the devices. In the cases where a device moves rigidly with a user's head, such as in the case of smart glasses, it is also possible to derive the user's head orientation from geo location and sensor data collected by the device.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. Similarly, issues identified with respect to one or more approaches should not assume to have been recognized in any prior art on the basis of this section, unless otherwise indicated.